Dental drill



Jan. l; v1929.

J. C. SHOTTON ET AL.

DENTAL DRILL Filed March 5, 1925 vments of this character.

Patented Jan. l, 1929.

JOHN c. sHoTToN, or LAKEWOOD, AND THEODORE sonner, oFcDEvELANDQoHIo;

DENTAL DRrLL.

Application led March 5, 1923. Serial No. 622,874.

This invention relates to drills and especially to drills of the type employed by dentists. It is the general purpose and object. of the invention to improve the construction and operating eiciency of instru- I A further and more limited object vof the invention is to provide al drill for use rby dentists which may be conveniently Vsterilized and maintained in a sterilized condition, and without disturbing the tool or any of the operating parts of the' drill.

We realize the foregoing objects and other objects which will be referred to in detail hereinafter through'the construction and ar- Arangement of parts shown in therdrawings,

wherein Fig. 1 represents Va central longitudinal section througha drill embodying our invention; Fig. 2 an elevation, with parts broken away, of the lower end of such drill, showing a slightV modification of. the shell-and-housing connection; Fig. 3 an elevation of the upper sectionvof therotatable spindle; and Fig. 4 an elevation of the drill chuck. i

Describing the various parts by reference characters, 1 represents generally a housing, called in the trade a handpiece having an enlarged upper end 2 and an enlarged lower end 3, saidenlarged ends constituting heads. The housing is provided with a'central bore 4. the'upper portion of which is yerqoanded toV provide two cylindrical chambers 2a and2b,

' the upper end of the `chamber2b being proy vided witha thread, indicated at- 2. Y f lower end of the bore 4 isalsoenlarged to The provide a cylindrical chamber 3a. The purposes of the cylindrical chambers will be eX-y plained hereinafter. The central bore 4 is for the reception of the uppersection 5 of a hollow4 spindle, and the chambers 2, 2b and 3a are provided for the accommodation of anti-friction thrust and radiall bearings.

Within the -chamber 2a isa radial bearing comprising theinner race 6, the outer race 7 fitted within 'theA wall of the chamber, and the interposed balls 8. A similar radial bearing is provided in the chamber 3a, said bearing comprising the inner race 9,' an outer race 10, andthe balls 11. s

Seated upon the annular shoulder 21 between the chambers 2a Aand 2b is the lowerv race 12 of `a thrust bearing, the Lipper race for suchbearing being formed in the lower i v n its lower end an upwardly -taperedf` recess surface of a heavy flange 13 which is carried at the lower end of` a'sleeve 14, the upper end of the-sleeve being split, as indicated at a 14, and threaded onto the spindle 5. This vthreaded connection enables .thesleeveand the flange 13 to bev adjustedrelatively tothe spindle to compensate for wear in the .bearf ings and upon the balls thereof. The upper 4 split and threaded end of thesleevemay be rigidly secured to the cooperating portion of the spindle by means vofa clamping collar 16 surrounding such end and having a set screw 17 extending throughthe collargand bearing at its inner end against the sleeve;

The upper surfaceof the flange 13 constitutes a vlower race for anupperthrust bearing comprising the ballsv 17 and the upperrace 18,y the said latter race being iad- Justably clamped within the chamber 2*.fby'

the lower end of a cap 19,'which is threaded .into the upper end. of the housing 1, there being washers 19ainserted between the flange 19b and the upper endof the head 2; by re- 1 f moving such washers as occasion may're.-A quire thethrust bearings may be adjusted to compensate -'for wear. The cap 1 9 is shown as provided with a cylindrical neck ange the Aspindle section'is provided with .a

threaded portion 5b, `the lower end of the spindle section. being downwardly tapered, as indicated at 5c. 1 f' The lower spindle section, indicated generally lat 23,A is shaped at'its upper-end to receive .therein` and to be- '.threaded. i upon the lowerend of the section 5, having an internal thread 23,a adapted: tov f receive the threadzfband having a tapered `orfrustoL conical `portion"23b adapt-ed to "fit about the tapered frusto-conical. portion 5C jof the section 5.- The lower end ofl the section-.23 is j v also tapered, as shown at 23C, and is provided with an (axial 'opening 23d.l through which vthe'small drill-tool may extend. f- Y Mounted within the upperxportion ofthe. y cylindrical bore ofthe spindle section 231s a` cylindrical plunger block 24 lhaving Within 24a. 'This tapered'recessfis adapted toen,- i

gage either of the tapered ends 25a, 251 of 'the drill chuck25.k Both ends of the-chuck are slotted longitudinally, as indicated at 25. The `chuck shown herein is symmetrical 4*as to both endsthereof, making it inimarterial which end is to be engaged by the plunger block 24 and which end is to hold the operating drill. i l

VvFor. the purpose of establishing an operative Aconnectionbetween the chuck and the spindlewe provide a screw 26 having an elongated stem or shank 262L and a knurled 1 head 27, the screw being threaded into and throughpthe lower end of the vspindle ineini ber `5. By rotating the screw in the appro priate direction, the block or plunger 24e will be fpressed Ydownwardly into engagement with the upper end of the chuck 25, forcing the lower tapered end of the latter into grip Y ping'engagementwith the drill tool and into Ydrivingrictional engagement with the inner taperedy seat 23,"provided therefor in the lower end ofthe spindle sections 28.

' 4The lower enlargementB Vof the housing` is l provided with an external thread 3l) on which there isthreaded the upper end of a shell.

i This shell Acomprises the upper internally threaded cylindrical portion 27,' a. frustorconicalV portion 27 extending downwardly fromsuch upper portion, and an extended cylindrical, portion 271-" surrounding the cylindrical portion of the spindle section 23,

` the lower end of the lshellheing also frustoconical, as shownat 27C, to'conform to the shape of the lower-endet the said spindle section. Instead of'being connected to the head 23by means of a thread, the shell may V"have tight sliding iit therewith, as indicated in Fig. 2; or any other convenient con nection fmay be employed between these parts. Y

This vshell constitutes an important part i ofour inventionsince it is the only part of the drill, aside romj the operating tool,

which engages the fiiiouth of tlie `patient.. This' shell canbe quickly and Vconveniently removed and can be sterilized and replaced Y without 'disturbing the tool or any/oi the.

Y operatinggp'arts ofthe drill; in fact, several shells maybe employed for the same drill and those not inl actualuse maybe sterilized andV kept sterile Aenabling the iisefoi a sterilizedv shell foreach patient without the delay n. incidental'tofV refsterilizinga-single shell.

Thelower end ofthespindle and the parts therein do not require sterilization, since they do not come ingcontact with the V'mouths of VtheV patients. y

The manner of connecting the two spindle 4 sections insures'a proper centering ci both parts of the'spindle and-the true running of the spindle as a whole. The Vradial beariiigsV insure practical -absenceof friction through the rotation of the drill spindle, while the arrangement' ofthe thrust bearings and the mannerof constructing the same minimize the fricticndue to thrusts exerted longitudinally of the drill and also provide a most effective ineans for adjusting and removing the parts to compensate from time to time fortlie wear incidental to such thrusts.

The reduced portion l oi' the housing and the tapered portion 27 L of the shell constitute a hand grip `by which the drill may be conveniently operated, with such reduced portion resting in the rcrotch between the thumby and `foreiinger and the thumb and fingers grasping such tapered portion ci' Vthe shell.

28 denotes a connectionhfor air, water orv other cooling fluid, said connection conimunicating with the upper end oi the uppery spindle section, which is provided wvith a Y central bore 29 for thepassage of the'tluid,

the lower end of the bore communicating with a bore 2ll1`provided inthe plunger ,block- 24. At itslower end, the Abore 2411 communicates by an inclined passage 241 with'an annular passage 24C surrounding theA said` block, which annular passage in turn comi municates with a vertical passage 30 -formed within the inner walloi2V the lower spindle section'and between the saine and the plunger block 2%.and the chuck 25. The lower charge the cooling. fluid againstthe 'operat- `end .of this Huid passage is adapted to disc ing burr orl drill tool and uponthe` field i or cavity. n ordinary causes of pain incidental to drilling a tooth by overcoming the heatdue to lriction;` and it may also` serve toremove VVthe chips incidental to the work.

This fluid serves to vremove the v The manner of mounting the spindle en-y j ables the instrument to be operated, practically without vibrationof the spindle and of the drill tool, thus removing one of the principal causes of pain incidental to the open ation of drilling teeth.y Also,"a ,convenient adjustment is provided between .the spindle and the bearings, wherebylongitudinal vibiation of tliespindle may beavoided, the lateral vibration being taken l,care ci by the 1 Furthermore, should: theV Y radial bearings. Y bearings become worn and needreplacenient,

the construction disclosed herein affordsV means whereby such replacementfmaybe,convenientlyiefected without -thernecessity :for l purchasing a new instrument. It should be noted also that, in our instrument, nooil is y needed VVfor any bearings below thel iiange 5f?. Y

This enables the instrument to hev operated Without the disagreeable incidentof having oilV enter the mouth `of the patient; and `this result may be attainedeven when air or other the shell ption7 it has been and claims in harmony with this assumption',

' but without anyizntention of limitingthereby the 'scope of the claims nor'the manner of use of the instrument.l d y Having thus described our invention,what we cla-im is: A Y

1. In an instrument of the character described,- the combination'of a housing having a-chamber at one Lend thereof, a spindle rotatably mounted in saidhousing and eX- tending through said chamber, thechamber having a lower end-thrust ball race sur-Vr rounding the said spindle and an upper endthrust ball race also surrounding said spin- -1 dle, -an intermediate ball race interposed between tlie first mentioned races and adjustably connected to said spindle, balls inter-V posed between the upper and lowerraces and the intermediate race,v and means for ladjusting the upper race.

is connected, the said sleeve being threaded on Isaid spindle, balls interposed betweenv said races, and means for securing the said sleeve in adjusted position upon said spindle.

3. In an instrument of the character set forth, the combination of a housing having a chamber at one end thereof, ,a spindle mounted'in said housing Vand chamber, ay

pair of end thrust bearings in said chamber, the said bearin's com risinO- a lower race surrounding said spindle, an upper race surrounding said spindle, an intermediate racev interposed between the first mentioned races,

a sleeveto which the vintermediate race is connected, the said sleeve, being split' and threaded on said spindle, means for clamping said sleeve upon said spindle, balls interposed between said races, and means for adjust-ing the race -which is adjacent to the enlarged end of said chamber.

4. In an instrument of the character de-` scribed, the combination of a housing havingV a chamber at its upper end, a spindle mounted in said housing and chamber, a double end-thrust bearing in said chamber,

- the bearing comprising a lower race, 'an upper race, an intermediate race interposed between the first-two races and -adjustably connected to said spindle, balls interposed between the intermediate raceand the upper and lower races, and a cap, through which said spindle extends, threaded into the upper end of the chamber and having a lange adapted to engage the upper race.

5. In an instrument of the character described, the combination` of a housing, a

spindle comprising an 'upper section mounted in said housing and vprojecting below 'the lower endthereof and' having below such end azcylindrical threaded portion and a'tapeied.

portion below suoli threadedportion, and a lower'f'spindle section threaded uponv the threaded portionof the first-mentioned section and having a tapered portion cooperat-y ing with the tapered lowerk end of the first section, therebyto `VVcenter said sections.

' (if In an instrumentfoi' the ,characterv del scribed, the combination cfa housing `halving la lower head,'a spindle comprising an upper section mounted in said housing and projecting belowand journaled inthe ysaid head and having below such head a cylindrical threaded portion and a tapered portion below such threaded portion, and a 'lower spindle section threaded upon the threaded portion of the first mentioned section and ist l having a tapered portion cooperating with the tapered lower vend of the first section thereby to center said sections, and a shell `removably connected lto `said head and surrounding the lower or operating portion. of

said spindlenand disconnected therefrom.`

.7. An instrument of thefcharacter vde-- scribed comprising a housing havinga cham ber at one end thereof, a spindle mounted in said housing and extending ybeyond such chamb'erthe said spindle having an outwardly projecting flange, outside said chamber, a yradial bearing having an inner race mounted on the spindle and resting on said flange, an outer race within said chamber, f

and balls interposed between said races.

18. In an instrument of the character described, the combination of a housing, a spindle rotatably mounted insaid housing and projecting below the same, a shell detachably connected to the lower portion of the housing and surroundingandl disconnected from the lower or operating portion of said spindle, and means for supplying fluid to the interior of said shell and-through thespace provided between the same and the lower portion of saidspindle and in ope-ra' tive yrelation to spindle. .v l

9. lIn an vinstrument of the character described, the combination of a housing, a spindle rotatably mounted in said housing and projecting below the same, a` shell detachably connected to said housing and sura tool supported by said means for supplying fluid to the interior of saidshell and from said shell into operative,v relation to a tool supported by said spindle,.-

10. In an instrument of the character deiio l rounding theloweror operatingportion of said spindle anddisconnected therefrom and' scribed the combination of a'housing having chambered ends, a spindle rotatably mounted in said housing and lprojecting' through the lower end of .the same, a radial bearing in each Fo said chambersh surrounding .said

spindle, one or more end thrust bearings-in one of said f chambers surrounding said spindle, meansv whereby the.` relative position ofthe spindle and of the end thrust bearing orj bearings maybe varied, a shell detahably Connected with said khousingandy covering the lower end of said spindle and a drill chuck arranged Within v said shell and adapted to ConneCtsaid spindle Witha drill.

11. In an instrument of the character described, the Combination of a` housing havinganzenlarged'upper end and an enlarged lower end and an intermediate portion adapted for receptionof a portion of the hand of the operator, a spindle l'mounted in Y and extending through said-ho'using,'said i the lower end of said spindle and means ar-v ranged Within said shell for Connecting said spindle with a drill. 'a A In testimony whereof, We hereunto affix our signatures. .Y

i JOHN o; sHoTTou THEoDoRE sonner.-` 

